Biot number
API · /prandtl-api
Heat Transfer Numbers API
healthy
3,766 Subscribers
Convective heat-transfer dimensionless numbers as an API, computed locally and deterministically. The prandtl endpoint computes the Prandtl number Pr = μ·cp/k (or ν/α), the ratio of momentum to thermal diffusivity that sets the relative thickness of the velocity and thermal boundary layers — air is about 0.71 and water about 7 at 20 °C. The grashof endpoint computes the Grashof number Gr = g·β·|ΔT|·L³/ν², buoyancy versus viscous forces in natural convection (for an ideal gas the thermal-expansion coefficient β ≈ 1/T). The rayleigh endpoint gives the Rayleigh number Ra = Gr·Pr, either from Gr and Pr or from the full natural-convection inputs, which governs the onset of convection (critical ≈ 1708 for a heated horizontal layer). The peclet endpoint computes the Péclet number Pe = Re·Pr = v·L/α, advection versus diffusion of heat. The biot endpoint computes the Biot number Bi = h·L/k and flags whether the lumped-capacitance transient model applies (Bi < 0.1). All inputs are SI. Everything is computed locally and deterministically, so it is instant and private. Ideal for thermal-engineering, HVAC, electronics-cooling, CFD, process-engineering and heat-transfer-education app developers, natural-convection and transient-conduction tools, and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. These are convective heat-transfer groups; for the Reynolds number alone use a Reynolds API and for surface-tension numbers a Weber API.
api.oanor.com/prandtl-api
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 68 ms
- Server probes · 24h
- Subscribers
- 3,766
- active
- Total calls
- 120
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 3,700 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 3,700 calls/month
- 2 req/sec
- Prandtl + Grashof + Rayleigh + Péclet + Biot
- No credit card
Starter
€6.80 /month
- 35,000 calls / month
- 6 requests / second
- Hard cap (429 above quota, no overage)
- 35,000 calls/month
- 6 req/sec
- Natural convection, lumped-capacitance
- Email support
Pro
€20.50 /month
- 172,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- 172,000 calls/month
- 15 req/sec
- CFD & electronics-cooling pipelines
- Priority support
Mega
€63.00 /month
- 1,040,000 calls / month
- 40 requests / second
- Hard cap (429 above quota, no overage)
- 1,040,000 calls/month
- 40 req/sec
- Platform scale
- Dedicated SLA
Built by
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api.oanor.com/mimetypes-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Heat Transfer Numbers API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Heat Transfer Numbers API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Heat Transfer Numbers API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Heat Transfer Numbers API cost?
Heat Transfer Numbers API has a free tier with 100 calls / month. Paid plans start at €6.80 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Heat Transfer Numbers API GDPR-compliant?
All requests to Heat Transfer Numbers API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.
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Code snippets
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curl https://api.oanor.com/prandtl-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."const res = await fetch("https://api.oanor.com/prandtl-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();$ch = curl_init("https://api.oanor.com/prandtl-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);import requests
r = requests.get(
"https://api.oanor.com/prandtl-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())Ratings
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